I believe the answer is 2 Correct?? If not can you explain it

Table 7 The following are cost data for four different size plants available to a competitive producer: Output AC1 AC2 AC3 AC4 50 $80 $95 $120 $1 50 100 3'5 80 100 120 150 65 60 T5 100 200 75 80 55 T5 250 90 100 30 90 6?. Refer to the above information {Table 1'} to answer this question. If the market price of this product is $60, which is the best size of plant? A. The plant represented by AC1. B. The plant represented by AC2. C. The plant represented by AC3. D. The plant represented byACA. E. It depends on whether it is the short run or the long run